A common problem with conventional cutting blades is the loss of sharpness or damage to the cutting edges of the blades encountered through use. Dulled or damaged cutting blade edges are less efficient in cutting through materials such as vegetation, and consequently place greater strain on the propulsion system driving the blade, and can even cause damage to the vegetation through the breaking instead of cutting of the individual stems. Conventional cutting blades must therefore be periodically replaced or reconditioned, both of which require the time-consuming process of removing and re-installing the entire blade. Either of replacing or reconditioning of the blade can be expensive particularly when multiplied by the number of times such process is needed over the lifetime of the cutting device.
A solution to the problems identified above is to provide cutting blades with replacement cutting edges. A number of designs for such replaceable cutting edges have been previously developed. However, the replacement cutting edge systems proposed to date have substantial drawbacks. For example, conventional replacement cutting edge systems provide only a single cutting edge, thus requiring replacement of the edge component whenever damage or dullness occurs. Moreover, conventional replacement cutting edge systems are configured for use in connection with a solid cutting blade design, which can be relatively expensive to produce.
In one embodiment, conventional rotary mower blades typically involve an external profile which, upon rotary motion at operating speeds, creates a lifting force at the ground surface. Such lifting force urges grass blades into an upright orientation so that the mower blade is more effective in cutting the grass, and cutting the grass evenly. The profile to enable such a lifting force typically includes an upwardly-inclined portion of the trailing edge of the blade opposite the leading cutting edge portion of the blade. Mulching mower blades use similar geometries, albeit with cutting recesses formed in the upwardly-inclined “lift” portion of the mower blade. The positioning of the “lift” portion, as well as the mulching portion, at the trailing edge of conventional lawn mower blades can result in a loss of lifting force in the time interval between a first “lifting” pass of the mower blade and a second “cutting” pass of the mower blade. In such circumstances, cutting and/or mulching performance may be compromised.
It is therefore a principal object of the present invention to provide a cutting blade apparatus having replaceable cutting edge components which engage at a leading edge of a hollow or tubular portion of the cutting blade.
It is a further object of the present invention to provide a cutting blade apparatus having replaceable cutting edge components which each include a plurality of cutting edges selectively indexable into an operating orientation.
It is another object of the present invention to provide a cutting blade apparatus having a replaceable cutting edge component which integrates a “lift” profile therewith.
It is yet another object of the present invention to provide a cutting blade apparatus having a replaceable cutting edge component which integrates a “lift” and a mulching profile therewith.